This disclosure relates to polycarbonate compositions, and in particular to copolycarbonate compositions having high glass transition temperatures, methods of manufacture, and uses thereof.
Polycarbonates derived from 2,2-bis(4-hydroxyphenyl)propane (“bisphenol A,” or “BPA”) are useful in the manufacture of articles and components for a wide variety of applications, from automotive parts to electronic appliances. 3,3-Bis-(4-hydroxyphenyl)-2-phenyl-2,3-dihydroisoindol-1-one (“BHPD,” also known as “N-phenyl-3,3-bis(p-hydroxyphenyl)phthalimide”) has also been used as a dihydric phenol reactant in the manufacture of polycarbonates, as described, for example, in U.S. Pat. No. 5,344,910 to Sybert. Polycarbonates derived from BHPD are high heat polymers, that is, polymers having a high glass transition temperature (Tg). Lin and Pearce, for example, have reported the synthesis of a BHPD-derived homopolycarbonate having a Tg of 250° C. (Journal of Polymer Science: Polymer Chemistry Edition, Vol. 19, and pp. 2659-2670 (1981).
There appears to be no reports in the literature of copolycarbonates derived from BHPD and another monomer that have a very high Tg, on the order of greater than about 250° C. It is expected that such polycarbonates would be suitable for use in high performance film applications such as organic light emitting devices (OLEDs), flexible printed circuits, flat panel displays, and backlit devices such as liquid crystal television and computer displays. High performance films preferably have excellent color, clarity, and resistance to heat, as well as low shrinkage and low coefficient of thermal expansion.
There accordingly remains a need in the art for polycarbonates suitable for use in high performance film applications, in particular polycarbonates with very high Tg and high temperature process compatibility. Other desirable features include high optical transparency, high color neutrality, low shrinkage, and low CTE. Still other desirable features include excellent smoothness when processed as films.